The world's biggest music stars have united in concerts around the globe to put pressure on political leaders to tackle poverty in Africa.

Concerts in 10 cities, including London, Philadelphia, Paris, Berlin, Johannesburg, Rome and Moscow played to hundreds of thousands of people.

A TV audience of several hundred million were watching the gigs, ahead of the G8 summit of leaders next week.

Bob Geldof said the day had been "full of hope and possibility and life".

In London Madonna, U2, Coldplay, Sir Elton John and Sting all performed.

Almost all of the singers involved took the opportunity to explain their reasons for performing.

Taking to the stage Madonna asked the crowd: "Are you ready to start a revolution? Are you ready to change history? I said, are you ready?"

She was joined on stage by 24-year-old Birhan Woldu, one of the starving children featured in the original Live Aid concert who was helped thanks to money raised 20 years ago.

In Philadelphia, Destiny's Child, Jay Z and Bon Jovi were among the big name performers.

Actor and singer Will Smith who hosted the concert said: "More than 200 hundred years ago, just down the block, America declared its independence.

"Today we all gather here to declare our interdependence. Today we hold this truth to be self-evident; We are all in this together."

In Canada, Bryan Adams and Neil Young entertained the crowd, while the Pet Shop Boys played in front of Red Square in Moscow.

In Tokyo, which had been the first of the concerts to start, Bjork performed, while in Berlin Green Day were among the big name stars.

In Johannesburg the biggest cheer of the night was for former leader Nelson Mandela.

He told the crowd that the G8 leaders had a "historic opportunity to open the door to hope and the possibility of a better future for all".

More than 200,000 people were at the concert in Hyde Park, London, while thousands more watched via big screens at locations around the UK.

The Who and Pink Floyd, who had reformed with original singer Roger Waters, were the final two bands to take to the stage.

The concert climaxed with a finale of Paul McCartney and all the other performers singing the chorus to the Beatles' hit Hey Jude.

Sir Paul said: "Everybody who's come along today has come for the right reason. We hope that the people, the heads of G8, are listening hard.

"They can't avoid this, they cannot have missed it and all you people who've come along for this message - we love you."

Other London performers included The Scissor Sisters, Keane, Travis, UB40, the Stereophonics and REM.

Earlier U2's Bono , who opened the London concert with Sir Paul McCartney, told the crowd: "This is our moment, this is our time, this is our chance to stand up for what is right.

"We are not looking for charity, we are looking for justice."

The concerts have not been without their critics, however, with some arguing that the campaign is over-simplifying the issue of global poverty.

Some anti-poverty charities and African leaders believe the event is too focused on money, rather than the problems of unequal trade, and good governance in Africa itself.

But Geldof told BBC News: "There's one plan. It's debt; trade and aid and governance. Prime, pump an economy, create good government and we'll get people out of poverty.

"That's what this is about. We'll jump if you jump and we're all jumping on behalf of those who can't even crawl."

More than 26.4 million people from around the world sent text messages on Saturday in support of the Live 8 campaign to cancel the debts of the poorest countries, setting a world record, organisers said.

The UN Secretary General Kofi Annan told the crowd in London: "This is really a United Nations. The whole world has come together in solidarity with the poor.

"On behalf of the poor, the voiceless and the weak I say thank you."

In Scotland, where the G8 leaders will meet, more than 200,000 protesters took place in a peaceful march urging the politicians to take action on poverty in Africa.